In order to manage the movement of a plurality of unmanned vehicles, unmanned dump trucks for example, for transporting soil in a wide area working site, such as a quarry and mine, a monitoring station is established as a ground station, and a vehicle monitoring system is structured such that this monitoring station manages and monitors these unmanned vehicles comprehensively.
As a method for controlling the traveling of these unmanned vehicles according to a predetermined traveling path in a working site, the following two types of methods have been used.
1) Guide wire (guide marker) traveling control system PA0 2) Autonomous traveling control system
The above 1) guide wire (guide marker) traveling control system controls the traveling of vehicles by actually disposing guide wires (guide markers), such as rails and magnetic nails, along a predetermined traveling path, so that deviation from the guide wire (guide marker) is minimized.
In this system, it is unlikely that the unmanned vehicles will extensively deviate from the predetermined traveling path, but initial investment is enormous since rails and magnetic nails must be disposed along the predetermined traveling paths, and also the predetermined traveling paths cannot be freely changed since the guide wires must be disposed all over again to change the predetermined traveling paths. Particularly, in such a working site as a mine, where the predetermined traveling paths are frequently changed, this problem is critical.
As a consequence, the above 2) autonomous traveling control system using positional measurement by dead reckoning, inertial navigation and GPS, is adopted in such a working site as a mine. This autonomous traveling control system controls vehicles to travel along predetermined traveling paths while comparing pre-stored position data of the predetermined traveling path with the actually measured positions of the vehicles, with the advantage that it is unnecessary to dispose the guide wires, therefore initial investment is low, and predetermined traveling paths can be freely changed compared with the 1) guide wire (guide marker) control system.
In this autonomous traveling control system, however, traveling control errors occur due to positional measurement errors, and it is more likely that the unmanned vehicles will extensively deviate from the predetermined traveling paths compared with the guide wire (guide marker) control system.
In a large scale mine, one traveling course, where vehicles travel on-coming to each other, is often disposed rather than disposing two parallel courses, so as to decrease investment for long distance courses.
In other words, there are two methods for setting a course for unmanned vehicles, setting two courses for going and coming traffic independently (see FIG. 17), and setting one course for going and coming traffic (see FIG. 16).
When one course is set for going and coming traffic, two lanes are created on one course so that vehicles can pass each other (see FIG. 18), or one lane is created on one course where if on-coming vehicles pass each other, one vehicle waits at a standby area (see FIG. 19).
In terms of investment to build a course, it is best to use only one lane for both going and coming traffic while creating standby areas, but in this case, productivity during operation decreases since a vehicle waits for an on-coming vehicle at a standby area. The other methods are not very different in terms of productivity during operation, but initial investment is much lower in building one course compared with building different courses for going and coming traffic.
When on-coming unmanned vehicles pass each other in this manner, there is a danger that one unmanned vehicle will deviate from the predetermined traveling path and cause a collision. To prevent such a collision of unmanned vehicles, the width of the course must be set extremely wide, which increases cost in establishing the course.
Also, in order to prevent a head on collision with an on-coming vehicle, the unmanned vehicles must pass each other while slowing down the respective vehicle speeds. This slow down of speed drops the work efficiency of the unmanned vehicles.
With the foregoing in view, it is an object of the present invention to prevent interference of vehicles when a plurality of vehicles are traveling on-coming to each other on a traveling path with a predetermined road width while minimizing an increase in cost caused by setting a wide course width, without a drop in work efficiency caused by decreasing velocity.